MATLAB: Replacing only certain instances of text within matlab character array

character arrayreplace

I have a large character array in matlab: 'lineDataA' – containing many different numbers.
I would like to find and replace all instances of the number '6002' and replace with '0', apart from the very first instance.
lineData = replace(lineDataA, '6002', '0');
This replaces all instances
And
where6002 = strfind(lineDataA, '6002');
Gives the position of all the instances. However I am not sure how to replaces all the instances except the first?
Many thanks for your help,
Rob

Best Answer

Method One: split the string
>> str = '___6002__6002___6002___6002__';
>> idx = regexp(str,'6002','once','end');
>> strcat(str(1:idx),strrep(str(idx+1:end),'6002','0'))
ans =
___6002__0___0___0__
Method Two: use a placeholder
>> str = '___6002__6002___6002___6002__';
>> str = regexprep(str,'6002','\b','once');
>> str = strrep(str,'6002','0');
>> regexprep(str,'\b','6002')
ans =
___6002__0___0___0__
Note that the original string must not contain \b.
Method Three: dynamic regular expression
>> str = '___6002__6002___6002___6002__';
>> regexprep(str,'(.*?6002)(.*)','$1${strrep($2,''6002'',''0'')}')
ans =
___6002__0___0___0__
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